A Sprouts Farmers Market in the U.S. state of Georgia is proving that using a CO2 transcritical refrigeration system in warm climates, even the ‘deep south’, can be both effective and energy efficient.
A success story: CO2 transcritical booster finds its home in southern U.S.
Sprouts, a grocery chain focusing on fresh and healthy foods with over 200 locations in the United States, opened its first store near Atlanta, Georgia, in July 2014. By adopting a CO2 transcritical booster system for its refrigeration needs, the company proved that this technology is equally effective in warm ambient temperatures.
The main challenge encountered by Sprouts was that CO2 transcritical technology is more commonly used in cooler climates and is not always an obvious solution in warm environments. However, with climate friendly regulations encouraging a shift toward alternative refrigerants, end users are keeping an open eye on CO2 transcritical booster systems.
To challenge this preconception, Sprouts employed Hillphoenix for the job, and the Georgia-based company, faced with the challenge of ensuring efficiency in the U.S.’s southern-most CO2 transcritical booster system installation, partnered with Emerson Climate Technologies to guarantee success.
About the system
The CO2 rack system includes:
Four semi-hermetic Copeland Transcritical CO2 compressors
Three Copeland Scroll ZO compressors
These fulfill high-pressure requirements and profit from CO2 thermal properties.
Emerson’s E2 Facility Management System:
Manages nearly 50 electronic case control units in the CO2 transcritical booster system
Optimises the facility’s overall energy management profile
Allows operators to run diagnostics and monitor the system remotely through Emerson’s ProAct Service Center
In addition to compressors and the E2 Facility Management System, Emerson also contributed:
Discharge Air Controller - operates in unison with the E2 system and is capable of controlling heat and cool stages, fans, dehumidification devices and economisers using on-board I/O
High-pressure CO2 controller - optimises high side pressures and liquid quality to the cases
XM Series Case Controls (pulse-width modulated) - integrates with the E2 system to maximise operating efficiencies through tighter temperature controls; present on nearly 50 cases
CoreSense Technology - advanced compressor diagnostics, protection and communications technology that allows technicians to make faster, more accurate decisions, resulting in improved compressor performance and reliability; present on all store compressors
Also key to the success of the overall system is the addition of an adiabatic condenser designed for high ambient temperatures. During the cooling process, the adiabatic condenser evaporates water into the air supply of an air-cooled condenser to pre-cool the air. The aim of this technology is to improve the system’s energy efficiency by keeping the CO2 below its critical point.
Lessons learned: what’s next for the future?
European stores have been using CO2 transcritical booster systems for nearly a decade. The U.S. commercial refrigeration sector, however, has been adopting these systems at a much slower rate. End users are cautious about shifting to CO2 transcritical booster systems, as they are concerned over operating pressures, maintenance levels and energy costs.
Such fears have proved unfounded: since the installation of the CO2 transcritical booster system in Sprouts’ Atlanta location, the company has operated its store efficiently and effectively. This success story is a testimony to the potential of using CO2 refrigerant in warmer climates.
About Emerson Climate Technologies
Emerson Climate Technologies, a business segment of Emerson, is one of the world’s leading providers of heating, air conditioning and refrigeration solutions for residential, industrial and commercial applications. The group combines best- in-class technology with proven engineering, design, distribution, educational and monitoring services to provide customized, integrated climate-control solutions for customers worldwide. The innovative solutions of Emerson Climate Technologies, which include industry-leading brands such as Copeland Scroll and White-Rodgers, improve human comfort, safeguard food and protect the environment.
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